• Ocean and Polar Research
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• v.36 no.1
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• pp.39-47
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• 2014

The black scraper Thamnaconus modestus was a commercially important fish species in the 1980s, but suddenly its commercial significance decreased in the 1990s mainly due to continuous overfishing. Recently, in order to reverse the depleted stocks of the black scraper and help the species recover, seed production technology has emerged. This has led to the farming of the black scraper in several parts of the southern coast of Korea. Since detailed research on its metabolism in relation to water temperature has been scanty, this was the investigative focus of the present study. The standard metabolism rates of the black scraper (9-10 months old, total length=$22.6{\pm}0.8cm$, wet weight=$140.3{\pm}13.9g$) were measured at seven different water temperature settings (12, 15, 17, 20, 23, 26, $28^{\circ}C$) to understand the relationship between metabolism and water temperature. Relationships between water temperature (WT) and oxygen consumption rate (OCR) were obtained as SOCR (weight-specific oxygen consumption rate) = 0.0117WT - 0.0135 ($r^2=0.9351$) and IOCR (oxygen consumption rate per individual) = 1.8160WT - 5.4007 ($r^2$ = 9428). The $Q_{10}$ (temperature sensitivity), an indicator of the sensitivity of biological function to temperature, was analyzed. In our experiment, when the water temperature increased, the $Q_{10}$ value decreased. The $Q_{10}$ value was 6.27 in waters where the temperature ranged from $12-15^{\circ}C$ and this was much higher than the values obtained in waters where temperatures ranged between (1) $15-23^{\circ}C$ and (2) $23-28^{\circ}C$. Consequently, it was shown that the black scraper is a warm water species and inhabiting waters in the temperature range from $15-28^{\circ}C$ is deemed appropriate.

• Ocean and Polar Research
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• v.35 no.2
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• pp.69-83
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• 2013

Metal concentrations in creek water, sewer outlets and core sediments were analyzed to identify the potential origin of metal pollution and to evaluate the extent of metal pollution and potential toxicity of Lake Shihwa. Mean concentrations for dissolved metals in creek water and sewer outlets were 1.6~136 times higher than those in the surface seawater of Lake Shihwa. Metal concentrations in creek water from an industrial region were also higher than those from municipal and agricultural regions, indicating that the potential source of metal pollution in the study area might be mainly due to industrial activities. The vertical profiles of metals in core sediments showed an increasing trend toward the upper sediments. Extremely higher concentrations of metals were observed in the vicinity of Banweol industrial complex. The results of a geo-accumulation index indicated that Cu, Zn and Cd were highly polluted. By comparing the sediment quality guidelines such as TEL and PEL, six metals such as Cr, Ni, Cu, Zn, Cd and Pb levels in core sediments nearby industrial complex exceeded the PEL value. Mean PEL quotient (mPELQ) was used to integrate the estimate of potential toxicity for measured metals in the present study. Mean PELQs in core sediments from Lake Shihwa ranged from 0.2~2.3, indicating that benthic organisms nearby the industrial complex may have been adversely affected.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.3
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• pp.185-195
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• 1975

The comparative studies Were conducted with respect to the artificial spawning early embryonic development, metamorphosis and growth of two species Meretrix lusoria and Cyclina sinensis collected from Inchon, Anmyon island and Buan areas from 1969 to 1974. The highest rate of artificial spawning of M. lusoria, which treated with a dilute ammoniun hydroxide(4/100-5/100N)-seawater solutions, was $25.0-33.3\%$, whereas in C. sinensis the rate of spawning was lower than that of M, lusoria under the similar experimental conditions$(12.5-19.0\%)$. However, the rate of artificial spawning of C. sinensis increased $40\%$ by repeated thermal stimulation. The rate of artificial fertilization of M. lusoria and C. sinensis showed highest value from those individuals which were treated with 1/1000N $NH_4OH$ solution. Their fertilized eggs, then, showed a normal development in the 1/1000N $NH_4OH$ solution. In the early embryonic development of M. lusoria and C. sinensis, the appearance of each of polar body, trochophore and D-shaped veliger were observed around 50min. 5-6 hours, and 23 hours after artificial fertilization respectively. The larval shell lengths of M. lusoria reached to $109,5{\pm}0.7\mu,\;144.6{\pm}1.3\mu$ and $208.0{\pm}0.0\mu$ around, 1, 11 and 20 days, after fertilization respectively. The larval shell lengths of C. sinensis reached to $110.5{\pm}0.6\mu,\;147.8{\pm}1.7\mu,\;and\;235.0{\pm}0.0\mu$ around 1, 10 ana 20 days, after fertilization respectively. The correlations of relative growth rate between the shell length(L) and sell height(H) found by the following simple formula from D-shaped veliger to metamorphosing stage. H=0.77L+6.82 for M. lusoria H=0.75L+8.50 for C. sinensis.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.19-25
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• 2000

The leaching behaviour of quinclorac was elucidated using soil columns. On top of each glass column packed with a rice paddy soil up to the 30 cm height were applied three different treatments of [$^{14}C$]quinclorac: quincloiac only (T-1), quinclorac adsorbed onto active carbon (T-2), and quinclorac adsorbed onto a mixture of active carbon and $Ca(OH)_{2}$ (T-3). Half of the columns were planted with rice plants for 17 weeks and half of them unplanted for comparison. Average amounts of $^{14}C$-activity percolated from tile soil columns without rice plants in T-1, T-2, and T-3 were 81.1%, 27.8% and 48.0%, respectively, of tile originally applied $^{14}C$, whereas those with rice plants grown were 36.8%, 9.6% and 11.0%, respectively, indicating that the leaching of [$^{14}C$]quinclorac was significantly affected by vegetation and by treatment with the adsorbents. The bioavailability of the herbicide to rice plants in T-1, T-2, and T-3 were 13.6%, 11.0% and 13.9%, respectively. The residue levels of quinclorac in the edible part of rice grains would be far less than the maximum residue limit (MRL, 0.5 ppm). After the leaching, the amounts of $^{14}C$ remaining in soil in with rice planting T-1, T-2, and T-3 were 36.3%, 73.7%, and 61.8%, whereas those without rice planting were 19.7%, 71.1%, and 52.3%, respectively. The balance sheets indicate that [$^{14}C$]quinclorac translocated to rice shoots would be lost by volatilization and/or in other ways in T-1 and T-3. The $^{14}C$-activity partitioned into the aqueous phase of the leachates collected from all treatments was less than 7% of the total, but it increased gradually with time in the case of rice growing, suggesting tile formation of some polar degradation products.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.4
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• pp.285-291
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• 2008

Objective: This study was performed to investigate whether cumulus morphology and oocyte diameter influence on in vitro maturation (IVM) of human germinal vesicle (GV) stage oocytes obtained from stimulated in vitro fertilization (IVF) cycles. Methods: Forty-one GV stage oocytes were obtained from 21 patients who received ovarian hyperstimulation and IVF. According to cumulus morphology before denudation, GV oocytes were classified into oocytes with dispersed cumulus cells (CCs) or compacted CCs. The diameters of denuded oocytes, both including and excluding the zona pellucida, were measured. All oocytes were cultured in commercial IVM medium. Maturation was defined as extrusion of the first polar body and the matured oocytes were inseminated by ICSI method. Results: Overall maturation and fertilization rate were 56.1% and 73.9%. Matured oocytes had significantly higher proportion of oocytes with dispersed CCs compared to oocytes failed to mature (91.3% vs. 55.6%, p=0.023). There were no significant differences of oocytes outer ($155.7{\mu}m$ vs. $152.4{\mu}m$, NS), inner ($114.3{\mu}m$ vs. $113.4{\mu}m$, NS) diameters and zona thicknesses ($41.3{\mu}m$ vs. $39.1{\mu}m$, NS) between matured and not-matured oocytes. In-vitro maturation rate of oocytes with dispersed CCs was significantly higher than which of oocytes with compacted CCs (67.7% vs. 20.0%, p=0.044). Oocyte diameters (outer and inner) and thicknesses were not related with maturational competence. Conclusion: Our results suggest that in vitro maturational competence of GV stage oocytes obtained from stimulated IVF cycles is closely associated with the cumulus morphology but not oocyte diameter.

• Journal of Yeungnam Medical Science
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• v.16 no.1
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• pp.94-100
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• 1999

The aim of this retrospective study was to determine whether a nephron sparing surgery might be feasible in patients with a small solid renal tumor. Materials and methods: Between 1988 and 1999, 21 patients with a radiologically detectable small solid renal tumor underwent enucleoresection, wedge resection and polar segmental nephrectomy. The mean age of the 11 men and 10 women in this study was 43 years (range 14 to 68). According to the preoperative radiological diagnosis, 15 among the 21 patients were considered to have renal cell carcinoma, 4 were considered to have angiomyolipoma, and in the remaining 2 patients, radiological differentiation of renal tumors was difficult. Among 15 patients considered to have renal cell carcinoma, 14 were found to have renal cell carcinoma and the remaining one patient was diagnosed as having oncocytoma on pathologic examination. Radiological determination of angiomyolipoma in four patients was confirmed to be correct on pathological examination. The 2 patients whose radiological diagnose was difficult were found to have cavernous hemangioma and angiomyolipoma. One patient with renal cell carcinoma developed arteriocaliceal fistula, the only immediate complication in this series and underwent nephrectomy on postoperative 10th day. The mean follow up duration for the 14 patients with renal cell carcinoma was 18.6 months (range:1-103). There was no other tumor involvement in the resection margins following the nephron sparing surgery. These results suggest that nephron sparing surgery provides an effective treatment for patients with a single, small, unilateral, localized renal tumor. Longer follow-up is suggested for more definite verification of the role of nephron sparing surgery.

• Ocean and Polar Research
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• v.37 no.1
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• pp.49-59
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• 2015

Spatial variation in the reproductive effort of Manila clam Ruditapes philippinarum is often closely associated with variation in the seawater temperature and food availability, which determines gonad maturity and the quantity of gamates produced during spawning. Previous studies also have reported that severe infection by the protozoan parasite Perkinsus olseni exerts a negative impact on clam reproduction, retarding gonad maturation or decreasing the reproductive effort. In the present study, we investigated impacts of P. olseni infection on the reproductive condition of Manila clam during a spawning season. Histology revealed that 54% of female clams in Wando off the south coast were in spawning, while only 10% of the female from Gomso and 0% of the female from Seonjaedo in Gyeonggi bay off the west coast were engaged in spawning at the end of May in 2004. Ray's fluid thioglycollate media (RFTM) assay was applied to assess P. olseni infection and indicated that the infection intensity in Wando ($3,608,000{\pm}258,000cells/g$ wet tissue) was significantly higher than the levels in Gomso ($1,305,000{\pm}106,000cells/g$ wet tissue) and Seonjaedo ($1,083,000{\pm}137,000cells/g$ wet tissue, p < 0.001). The size of the ripe female follicle determined from histology was significantly smaller in Wando ($0.032mm^2$) compared to the sizes in Gomso ($0.059mm^2$) and Seonjaedo ($0.052mm^2$, p < 0.05). Accordingly, the number of ripe eggs in the follicle was significantly fewer among clams in Wando (14) compared to the numbers determined in Gomso (23) and Seonjaedo (22). The absolute quantity of egg in ripe clams from Wando (31.01 mg) was also significantly smaller than Seonjaedo (61.79 mg) and Gomso (133.3 mg). Quantity of total protein, carbohydrate, and lipid in the tissue in the Wando samples was significantly smaller than the quantities determined in Gomso and Seonjaedo (p < 0.001). The observed poor reproductive condition and proximate tissue composition of the females in Wando were, in part, explained by the extremely high level of the parasites, sapping the ability to store energy in the host tissues, which is used in tissue growth and the egg production.

• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.405-414
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• 2008

To better understand the physical processes that control the high-latitude lower thermospheric dynamics, we analyze the divergence and vorticity of the high-latitude neutral wind field in the lower thermosphere during the southern summertime for different IMF conditions. For this study the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEG CM) is used. The analysis of the large-scale vorticity and divergence provides basic understanding flow configurations to help elucidate the momentum sources that ulti-mately determine the total wind field in the lower polar thermosphere and provides insight into the relative strengths of the different sources of momentum responsible for driving winds. The mean neutral wind pattern in the high-latitude lower thermosphere is dominated by rotational flow, imparted primarily through the ion drag force, rather than by divergent flow, imparted primarily through Joule and solar heating. The difference vorticity, obtained by subtracting values with zero IMF from those with non-zero IMF, in the high-latitude lower thermosphere is much larger than the difference divergence for all IMF conditions, indicating that a larger response of the thermospheric wind system to enhancement in the momentum input generating the rotational motion with elevated IMF than the corresponding energy input generating the divergent motion. the difference vorticity in the high-latitude lower thermosphere depends on the direction of the IMF. The difference vorticity for negative and positive $B_y$ shows positive and negative, respectively, at higher magnetic latitudes than $-70^{\circ}$. For negative $B_z$, the difference vorticities have positive in the dusk sector and negative in the dawn sector. The difference vorticities for positive $B_z$ have opposite sign. Negative IMF $B_z$ has a stronger effect on the vorticity than does positive $B_z$.

• Korean Journal of Cognitive Science
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• v.12 no.3
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• pp.29-46
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• 2001

This study attempted to demonstrate that the integration of the two premises in linear syllogism is mediated by the middle term the term that is repeated in the two premises. In Experiment 1. we examined whether representing the middle term is more important than representing the end terms. We asked a question to each premise. Depending on the order of the questions either the two end terms or the middle term became the answer in both premises. Participants solved the problems better when the middle term became the answer suggesting that it is more important to represent the middle term than the end terms. In Experiment 2 we examined whether additional processing is needed for the integration beyond establishing co-referential link through the middle term. We pronominalized the middle term in the second premise and provided two kinds of information to disambiguate the pronoun. In the direct information condition we provided information about who the pronoun is whereas in the indirect information condition we provided information about the relative location of the pronoun. Participants solved the problems more quickly in the indirect information condition than in the direct information condition indicating that mere co-referential link was not enough and that the relative location of the middle term needs to be computed for the integration of the two premises.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.2
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• pp.259-266
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• 1998

A study on the biological and chemical characteristics in the middle last Sea of Korea was carried out at 31 stations in October $11\~18$, 1995 on board the R/V Tam-Yang. The chlorophyll a concentration, new and regenerated production, and the vertical diffusion of nitrate from the thermocline structure were investigated. From the vertical distribution of chlorophyll a, subsurface maxima were observed near the thermorline at most stations including the frontal zone, except at the southern stations where the maximum chloropyll a concentration occurred at the surface, The nanophytoplankton was the most dominant fraction comprising $83.5\%$ of total phytoplankton cell numbers, but netphytoplankton were common at the southern stations where the dominant species were Rhizosolenia sp. Nitrogenous new production and regenerated productions were measured using the stable isotope $^{15}N$ nitrate and ammonia uptake method. The vertically integrated nitrogen production varied between 8.470 and $72.945\;mg\;N\;m^{-2}\;d^{-1}$. The f-ratio, which is the traction of new production from primary production, waried between 0.03 and 0.72, indicating that $3\%$ to $72\%$ of primary production was supported by the input of nutrients from below the euphotic zone and the rest are supported by ammonia recycled within the euphotic layer. This range of f-ratio encompasses from extremely oligotrophic to eutrophic area characteristics. The differences in productivity and f-ratio among stations were related to frontal structure and the bottom topography. The values were high near the frontal zone and low outside of it, and the station near Ulleng Island showed the highest f-ratio. Vertical diffusion coefficients were calculated from both the water column stability (Kz-1) of King and Devol's equation (1979) and new nitrogen requirement (Kz-2). The values of Kz-2 ($0.11\~0.55\;cm^2/s$) were relatively low compared to the values reported previously.